#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main()
{
	int i;
	double p, m;
	p = 1; m = 0;
	for (i = 1; i<= 20; i++)
	{
		p *= i;
		m += p;
	}
	printf("Sum is : %lf\n", m);
	return 0;
}